A comparative study of two third-generation anti-hepatitis C virus ELISAs.

The sensitivity and specificity of two third-generation screening tests for the detection of antibody to hepatitis C virus (anti-HCV) was evaluated in a side-by-side study (Abbott HCV EIA 3.0/Ortho HCV ELISA 3.0). Specimens that were reactive in either ELISA were then retested by the other ELISA, and confirmed by RIBA-3. The screening of 15,540 serum samples from healthy blood donors showed a significantly lower number of reactive cases tested by Ortho (21 out of 8,805, 0.24%), than tested by Abbott (35 out of 6,735, 0.52%). In the side-by-side comparison, we found that significantly (p = 0.005) more Ortho-positive samples were also reactive in Abbott (14/21, 66.6%), than in Abbott followed by Ortho (7/35, 20%). Moreover, the RIBA analysis revealed a significantly (p = 0.014) higher number of RIBA-positive specimens among those reactive in Ortho 10/21 (47.6%), than among those reactive in Abbott 6/35 (17.2%), thus the former provides a greater positive predictive value. However, we did not observed differences in the sensitivity between Abbott and Ortho, because all RIBA-positive samples demonstrated reactivity in both ELISAs.